This invention relates to a high-speed data communication system, and particularly to a method of reducing data-dependent jitter and increasing frequency amplitude in a self-series terminated (SST) driver.
Some existing drivers/transmitters use current sources or voltage amplifiers that require a certain amount of voltage overhead to insure that the driver remains in the linear operating region of the current source or voltage amplifier. This voltage overhead increases the driver's power dissipation and decreases the maximum signal amplitude. Self-series terminated (SST) drivers are another class of voltage mode drivers. SST drivers operate in the voltage mode and are configured to solve power dissipation issues. However, these SST drivers can suffer from a data-dependant jitter phenomenon. In particular, these SST transmitter/drivers contain a half-rate-to-full-rate data serialization function incorporated into the design. Remaining data dependant stored charge from previous bits is the source of the data dependant jitter that has been observed in this type of design.